This invention relates to electrical connectors and, more particularly, to a switch arm connector block for mounting a plurality of spring switchblades in a predetermined array for sequential cooperation with an electrical appliance timer cam.
Electrical appliance timers employ rotary cam elements which actuate cycle control switches having movable or active blades which ride on the cam elements. The cam elements are arranged on the surface of a rotary drum cam of the type set forth in U.S. Pat. Nos. 3,390,243 and 3,431,372, or a rotary disc cam of the type set forth in U.S. Pat. No. 2,703,347. Each active blade extends as a cantilever from a terminal block and, upon cam-actuated movement, makes or breaks contact with one or more associated fixed blades which also extend as cantilevers from the terminal block.
Appliance manufacturers require increasingly more complex cycles in appliances, such as clothes washers and dryers, thus necessitating increasingly more complex switching functions in the timer, which is alloted a finite amount of space in the appliance by the design engineer. Timer manufacturers have been faced with the problem of compressing a large number of switch arms into a relatively small space for operation by the rotary cam elements, and, because of the increased number of cycles of the appliance, providing compact and simple bussing arrangements between the various switch elements without complicated wiring schemes or the provision of additional switch elements or cams.
Prior art practices, therefore, typically provide a connector block having compact bussing associated with a terminal connector block. Examples of such arrangements may be found in U.S. Pat. Nos. 3,431,372; 3,390,243; and 3,771,102. These prior art arrangements include a plurality of active and fixed blades which are molded into plastic insulating wafers so that the blades are coplanar in the wafer and extend from one end of the wafer as cantilevered switchblades and extend from the other end of the wafer as connecting blades for cooperation with the disconnect-connect portion of a wiring harness. A series of wafers are stacked together to form a completed terminal switch block, with the blades arranged in coplanar ranks and their axes in coplanar files.
In U.S. Pat. Nos. 3,390,243 and 3,431,372, there is disclosed a bussing arrangement which enables bussing between selected blades in different vertical alignment, or in the same alignment, by stabbing through window openings in the wafers to engage projecting tabs in some of the openings. While this arrangement performs satisfactorily, connecting portions of the bussing strips lie in an exposed condition over the assembled connector block. Moreover, the electrical connection is a frictional edge contact connection, which is not an ideal electrical connection. Still further, since the window openings through the wafers are made during an injection molding operation, plastic flash may cover portions of the switch body portions which are intended to be electrically connected by the busses.
In U.S. Pat. No. 3,771,102, there is disclosed an end bussing arrangement wherein buss bars are provided in channels molded into a connector cap for the terminal block. The buss bars are loosely fitted in the channels and, again, frictional contact is relied upon for the electrical connection. If the cap is removed from the terminal block, there exists the possibility of the bussing bar's falling out of its proper channel.